The Properties of Middle Digraphs

Abstract

Let $D$ be a strongly connected digraph with order at least two. Let $M(D)$ denote the middle digraph of $D$, and let $\kappa (D)$ and $\lambda (D)$ denote the connectivity and arc-connectivity of $D$, respectively. In this paper, we study super-arc-connected and super-connected middle digraphs and the spectrum of middle digraphs.